Inverters · India
Homeowners compare panels and accept whatever inverter arrives. That is the wrong way round: the inverter decides how your array behaves day to day, and it is the one component you should expect to replace.
Three types, one usual answer
| String | Micro | Hybrid | |
|---|---|---|---|
| Manages | A group of panels together | Each panel individually | Group, plus a battery |
| Handles partial shade | Less well | Best | Less well |
| Cost | Lowest | Highest | Higher than string |
| Electronics located | On a wall, in shade | On the roof, in the heat | On a wall, in shade |
| Gives outage backup | No | No | Yes, with a battery |
| Usual fit for Indian homes | Most systems | Shaded or multi-facing roofs | If backup matters |
Last reviewed
This is the point that most often looks like a mistake on a quotation. If you have around 3.3 kW of panels, you may well be offered an inverter rated somewhat lower — and that is deliberate, not a shortcut.
Panels are rated under standard test conditions that your roof never reproduces. Real output is reduced by heat, dust, haze, angle and age, so an array almost never delivers its nameplate figure. An inverter sized exactly to the nameplate would therefore spend its whole life lightly loaded, which is both wasteful and slightly less efficient.
A modest excess of panel capacity over inverter rating is normal practice. What you want is a designer who can state the ratio they have used, confirm it sits within the inverter manufacturer's permitted limits, and explain it without becoming defensive. What you do not want is an inverter so undersized that it clips off generation on every clear morning.
A string inverter manages a whole group of panels as one, which means the group is influenced by its weakest member. If a water tank shadow crosses two panels at four in the afternoon, that shadow affects more than just those two.
Microinverters work panel by panel, so a shaded module mostly hurts only itself. The cost is real, and so is the fact that the electronics then live on the roof in full Indian heat rather than on a shaded wall.
The honest summary: for a single clean plane with no meaningful shading, a good string inverter is the sensible and cheaper choice. Where shade is genuinely unavoidable, per-panel electronics earn their premium. Shade deserves proper attention either way, because its effects are worse than most people expect — the mechanism is explained in how rooftop solar works.
A maximum power point tracker continuously finds the best operating point for a group of panels. Each tracker does that job independently for its own group.
The practical consequence is straightforward. Panels facing different directions, or subject to different shade patterns, should sit on separate trackers, because the optimum for an east-facing group at nine in the morning is not the optimum for a west-facing one.
So: one clean plane facing one way needs one tracker. An array split across two orientations, or with one section shaded in the afternoon, genuinely benefits from more. If your roof is not a simple rectangle, this is a question worth asking explicitly, alongside the area arithmetic in roof area required.
Your inverter has to match the supply you actually have. Most Indian homes are single phase, and typical residential system sizes sit comfortably there.
Larger systems commonly require three-phase supply, and if your connection is single phase, obtaining three phase is a separate DISCOM process with its own cost and timeline — not an afterthought at installation. Where that threshold begins to bite is covered in 10 kW pricing.
Check the sanctioned load and phase printed on your bill before agreeing a capacity, for the reasons set out in net metering.
Homeowners chasing subsidy tend to interrogate module eligibility thoroughly and then wave through the rest of the system. Eligibility rules for assisted residential installations cover the equipment used, not the panels alone.
Get written confirmation that both the modules and the inverter satisfy the requirements of the scheme you are claiming under, and keep it with your commissioning documents. The failure modes here are described in ALMM and DCR, and the consequence of getting it wrong is a delayed or rejected claim rather than a small inconvenience.
Heat is the enemy. An inverter mounted in direct sun on an exposed wall will run hotter, age faster, and may throttle its own output to protect itself on exactly the blazing afternoons when you expected most generation.
Specify a location that is shaded, ventilated, dry and reachable for service. Near the coast, keep it away from direct salt-laden air. Being able to actually see the display or reach the app also matters, because monitoring generation is how you catch a fault before it costs you a season.
Panels are warranted for output over decades. Inverter warranties run for a few years, extendable at extra cost. The gap between those two facts is the most predictable expense in rooftop solar.
Assume at least one inverter replacement across the life of the plant and put it in the arithmetic from the start. A payback figure that contains no replacement is not wrong by a rounding error, it is wrong by a component. The full picture on warranty lengths is in warranty and lifespan.
Settle the capacity your bill justifies first, then specify the inverter around it. Run the free home check. Related: panel count · system types · choosing an installer.
The inverter is normally rated at or slightly below the total panel capacity rather than above it, which surprises people who expect the two numbers to match. Panels almost never produce their full rated output in real conditions, because heat, dust, angle and haze all reduce it, so an inverter sized exactly to the nameplate would spend its life underworked. A modest amount of panel capacity above the inverter rating is deliberate and normal. What matters is that the designer can explain the ratio they have chosen and that it sits inside the manufacturer's permitted limits.
They solve a specific problem rather than being generally superior. A string inverter manages a whole group of panels together, so the group tends to be held back by its weakest member, which matters when part of the roof is shaded at some point in the day. Microinverters work per panel, so a shaded panel affects mainly itself. The trade-off is cost and the fact that the electronics sit on the roof in the heat. For a simple unshaded Indian terrace facing one direction, a good string inverter is usually the sensible and cheaper choice.
A maximum power point tracker is the part of the inverter that works out the best operating point for a group of panels and holds it there. The practical significance is that each tracker manages its group independently, so panels facing different directions, or sitting under different shade patterns, should ideally be on separate trackers. If your roof is a single clean plane facing one way, one tracker is sufficient. If the array is split across two orientations or a section is shaded in the afternoon, having more than one genuinely improves output and is worth asking about.
Considerably less than the panels, and this is the most important planning point about it. Panels are commonly warranted for output over about twenty-five years, while inverter warranties run for only a handful of years with paid extensions available. Because it is a hard-working electronic device operating in Indian ambient temperatures, expect at least one replacement across the life of the system. That replacement cost belongs in your payback arithmetic from the beginning rather than arriving as an unwelcome surprise a decade in.
Somewhere shaded, ventilated, dry and reachable. Heat shortens the life of the electronics and can make the unit reduce its own output to protect itself on the hottest afternoons, which is exactly when you wanted the generation. Mounting it in direct sun on an exposed terrace wall is therefore a poor choice even though it is convenient during installation. It also needs to be accessible for service and close enough to read, and in coastal areas it should be kept away from direct salt-laden air.
It can, because eligibility rules for assisted residential systems cover the equipment used and not only the panels. Homeowners often focus entirely on module compliance and assume anything will do for the rest of the system, which is a route to a rejected claim or a delayed inspection. Ask for written confirmation that both the modules and the inverter meet the requirements applying to the scheme you are claiming under, and keep that confirmation with your commissioning paperwork.
If storage is a genuine possibility it is much cheaper to plan for it now than to retrofit. An ordinary grid-tied inverter cannot charge or manage a battery, so adding one later usually means replacing the inverter or adding separate battery-side equipment, plus wiring changes to separate the circuits you want backed up. A hybrid unit costs more at the outset and is unnecessary if you are confident you will never want backup. The decision to make deliberately, rather than by default, is whether outage cover matters to your household.
